Magnetic resonance imaging (MRI) is an imaging technology involving biomagnetism and nuclear spin that has grown rapidly with the development of computer technology, electronic circuit technology, and superconductor technology. MRI uses a magnetic field and radio frequency (RF) pulses to cause nutation of processing hydrogen nuclei (e.g., H+) in human tissue to generate RF signals, which are processed by computer to form an image. When an object is placed in the magnetic field, if the object is irradiated with appropriate electromagnetic waves to make the object resonate, and the electromagnetic waves released thereby are analyzed, it is possible to discover the positions and types of the atomic nuclei that form the object. On this basis, a precise three-dimensional image of the interior of the object may be drawn. For example, MRI may be used to scan a human brain to obtain a moving image of contiguous slices, beginning at the top of the head and going all the way to the base thereof.
Compared with other medical imaging products such as X-ray and computed tomography (CT) products, a MRI system may provide high-contrast images of different soft tissues. Full-body imaging matrix is an effective technology for performing a full-body scan with a MRI system. The MRI system offers the largest coverage, the highest signal-to-noise ratio, and the fastest speed. Multi-channel local coil technology is also an important constituent part of full-body imaging matrix technology. In the course of scanning, a user will often connect to the system multiple local coils that may be used simultaneously, and select some of the units of each local coil when examining a specific part of the body. During this process, the user does not need to change local coils or reposition the patient during scanning. Therefore, full-body imaging matrix technology is able to freely switch the signals received by the local coil unit of interest to the receiver.
In certain MRI systems, there are numerous types of local coil arrangements, with local coils of different types having different mechanical structures or different numbers of receiving channels. Furthermore, flexible local coils are the most commonly used and convenient type of local coil, and may be used to image various parts of the body such as the shoulder joint, the abdomen and the knee joint, owing to their property of being flexible and bendable. Moreover, since flexible local coils are lightweight and inexpensive, many clinical applications opt to substitute two or more flexible local coils for dedicated local coils used to image specific parts of the body, such as head/neck coils and limb coils.
One way of making a MRI system compatible with multiple local coils has been to increase the number of system slots and the number of receiving channels. A shortcoming of this method is that it increases the cost of the patient table and the receiving assembly, while making research, development, and design more complicated. Secondly, since the number of system slots in a MRI system is limited, the number of local coils that may be connected simultaneously to a single MRI system is also limited. Moreover, each local coil has a long cable carrying a plug; laying out and using multiple local coils together with the cables thereof is not only very troublesome for the operator, it also has a significant effect on the comfort of the patient.